The recent oral arguments for Gill v. Whitford left court–watchers unsure if the Supreme Court would strike down excessive partisan gerrymandering. Gill v. Whitford’s impact goes far beyond Wisconsin: as previously noted, there is a lawsuit against Maryland’s 6th Congressional District for excessive partisan gerrymandering. Though the 4th Circuit declined to throw out the congressional voting map that created the 6th Congressional District, the case does not end there. The 4th Circuit wants to wait and see how the Supreme Court rules in Gill v. Whitford before issuing a ruling, and the plaintiffs announced their intent to appeal to the Supreme Court. If the Supreme Court sides with the plaintiffs in Gill, what would happen to the Maryland case?

First and foremost, the Court, whether it is the 4th Circuit, or the Supreme Court, would look at Maryland’s efficiency gap. The efficiency gap is determined through a simple equation:

To determine the number of wasted Republican votes throughout the state, the Court would add up all the votes Republicans wasted in each district; it would do the same for Democrats. To determine the number of wasted votes in each district, the Court looks at who won the district. The way the Court would calculate the number of wasted votes for the party that won the district (which in MD will almost always be a Democrat) is to subtract the number of votes the Democratic candidate needed to win from the amount the Democratic candidate actually received. For the party that lost the district (which in MD will almost always be a Republican), the Court would just use the total amount of votes cast for the Republican candidate, since every Republican vote is wasted.

For example, look at Maryland Congressional District 2’s results in the 2016 election. A grand total of 309,480 votes were cast. For the Democratic candidate to win the district, he would need roughly 157,834 votes. Thus, when subtracting this from the number of votes the Democratic candidate actually received (192,183), the Democrats wasted 34,349 votes in District 1. The Republicans received 102,577 votes in a district they lost, so they wasted 102,577 votes.

After doing this for every district, The New York Timescalculated that the Democrats had roughly 510,000 wasted votes in the 2016 election, while the Republicans had roughly 789,000 wasted votes. The Times subtracted 510,000 from 789,000, and determined the Republicans wasted 279,000 more votes than the Democrats did.

From there, the Court would divide the number of wasted votes by the total number of votes cast in the election. In this case, the Times determined the efficiency gap was 10.7%. The efficiency gap represents the percentage of extra seats the Democrats won solely because the district boundaries were drawn to favor Democrats and waste fewer of their votes. Thus, for practical purposes the efficiency gap is around 11%.

The creators of the efficiency gap said that an efficiency gap of 7% or higher would be enough to constitute an unconstitutional partisan gerrymander. What is unclear is if the efficiency gap, by itself, is enough. The Wisconsin District Court did not believe the efficiency gap by itself was enough; instead, it used a three-prong test asking if a districting plan was intended to severely impact individual’s votes based on party, if it had that effect, and if the districting plan could not be justified on other legitimate legislative grounds. The District Court used the efficiency gap to decide on the effect question.

If the Supreme Court uses the efficiency gap in this way, then Maryland’s 6th Congressional District may be unconstitutional. Intent is easy to establish; former governor O’Malley admitted his intent to create a district where Democrats would win. That said, the intent question is if the districting was intended to severely impact individual’s votes based on party, not if the districting was just intended to create a safe district. So, intent depends on how the Court interprets it. As the efficiency gap is higher than 7%, the districting plan had the effect of severely impacting Republicans’ vote. With the “other legitimate legislative grounds” prong, the reviewing court would have to look at the other factors that could explain the disparity between number of votes cast by a party and the number of seats that party holds. These factors include the Democratic Party’s tendency to cluster in cities, and if the legislature had other available means of redistricting that would not have limited Republican power as severely. This could potentially be the hardest part of finding the 6th unconstitutional, because it is unclear if the legislative history here is strong enough.

If the Supreme Court just uses the efficiency gap, the plaintiffs in the MD case would probably win, as the efficiency gap was over 7%. The only way for the plaintiffs to lose in a just efficiency gap analysis would be if the Court decided the efficiency gap had to be higher than 11% to be unconstitutional. However, at oral arguments for Gill v. Whitford, Chief Justice John Roberts, as well as Associate Justices Samuel Alito and Neil Gorsuch seemed dismissive of the efficiency gap, indicating that the standard is not likely to just be the efficiency gap.

Whether the Supreme Court/4th Circuit will find Maryland’s 6th Congressional District unconstitutional ultimately depends on if the Supreme Court in Gill decides for the plaintiffs and adopts the efficiency gap. Assuming the Court does, it is plausible that either the 4th Circuit or the Supreme Court will find that Maryland’s 2011 redistricting that created the current 6th Congressional District, was an unconstitutional partisan gerrymander.